The present invention relates to an instrument, herein called a surgical stapler, for closing a puncture in a liquid-carrying vessel by applying a staple across the puncture so as to effect a closure. The invention relates particularly to surgical staplers for closing punctures in blood vessels.
When performing catheterisation procedures, such as angiography or angioplasty, a catheter is generally introduced into the vascular system by first penetrating the skin, underlying tissues and blood vessel with a sharpened hollow needle. Next, a guidewire is commonly inserted through the lumen of the hollow needle and is caused to enter the selected blood vessel. Subsequently the needle is typically stripped off the guidewire and a combination of a dilator and/or introducer (or an introducer alone) are fed over the guidewire and pushed through the skin to enter the blood vessel. The guidewire can then be removed and a desired catheter to carry out the procedure is fed through the lumen of the introducer and advanced through the vascular system until the working end of the catheter is appropriately positioned. Following the conclusion of the catheterisation procedure the working catheter will be withdrawn and subsequently the dilator and/or introducer will also be removed from the wound. Following this procedure the vessel puncture must be closed in order to prevent loss of blood through the puncture hole.
Typically the wound is closed by maintaining external pressure over the vessel until the puncture naturally seals. This procedure can take approximately 30 minutes with the length of time usually being greater if the patient is hypertensive or anticoagulated. The procedure can also be uncomfortable for the patient and involves costly professional time on the part of the hospital staff. Other pressure techniques such as pressure bandages, sandbags or clamps have been employed but these also involve ensuring the patient remains motionless for an extended period of time and is monitored to ensure the effectiveness of the procedure.
A number of devices have been developed in recent times which provide an obstruction in the area of the puncture in order to prevent bleeding. For example, U.S. Pat. Nos. 4,852,568 and 4,890,612 disclose a device which utilises a collagen plug which when placed at the blood vessel opening absorbs body fluids, swells and affects a seal. Other plug like devices, for example U.S. Pat. No. 5,222,974 and U.S. Pat. No. 5,282,827, describe a plug and anchor device, the anchor being positioned inside the vessel and the collagen plug outside the vessel thereby sandwiching the puncture between both and effecting a closure.
WO 98/17179 discloses a surgical stapler having a blood locator tube adjacent the stapling head. A guidewire passes through an opening at the end of the tube and up through a hollow bore in the tube, so that the stapler can be fed onto the guidewire and down onto the puncture site. When the device reaches the puncture site, the tip of the tube enters the blood flow within the artery and blood passes through the tube and out of the distal end at a point visible to the clinician. The clinician can then actuate the stapling mechanism in the knowledge that the stapling head is at the puncture site in the arterial wall.
It is an object of the present invention to provide an instrument for closing a puncture in a liquid-carrying vessel by stapling.
According to the present invention there is provided a surgical stapler comprising a shaft, a locator slidable axially of the shaft between a forward position wherein the locator projects beyond a free end of the shaft to enter a puncture site in a liquid-carrying vessel in a human or animal, thereby to locate the free end of the shaft at the puncture site, and a rearward position wherein the locator is retracted relative to the shaft, a surgical staple straddling the locator and slidable forwardly thereon, said staple having forwardly pointing legs disposed respectively on opposite sides of the locator, an anvil against which the staple may be deformed to staple together opposite edges of the puncture site, and an actuator for driving the staple forwardly along the locator into deforming engagement with the anvil and for retracting the locator in co-ordination with the movement of the staple such that the locator is withdrawn from between the legs of the staple in time to allow the legs of the staple to staple together opposite edges of the puncture site.
In another aspect the invention provides a method of stapling closed a puncture site in a liquid-carrying vessel in a human or animal body, comprising the steps of:
introducing a stapling mechanism to the location of the vessel;
positioning the stapling mechanism at the puncture site by means of a locator associated with the stapling mechanism and projecting forwardly thereof, the locator sensing the position of the puncture site by entering the vessel at the site;
delivering a staple to, and deforming the staple to close, the puncture site; and
in co-ordination with the delivery and deformation of the staple, withdrawing the locator from the puncture site such that the locator is fully withdrawn from the vessel by the time the staple is fully deformed to close the puncture site.
Preferably, the steps of delivering and deforming the staple and in co-ordination therewith withdrawing the locator are effected by operating a single control on a stapler actuating mechanism.